Many real-time multimedia and interactive applications, such as video streaming, IPTV, VoIP, videoconferencing, etc., require some kind of Quality-of-Service (QoS) guarantees over the Internet. For example, a video stream is transmitted from a source to one or many users via networks paths in the Internet. Excessive latency or low bandwidth of the paths may result in degradation of service. For example, the users may experience a stoppage, blackout, or other degradation of the video when viewing. Thus, QoS guarantees for network paths, such as guaranteeing a maximum latency for a network path, guaranteeing minimum bandwidth for a network path, or guaranteeing a maximum loss are beneficial when providing real-time multimedia and interactive applications.
Although there have been recent advances in QoS provisioning in the Internet through Intserv or Diffserv, it is far from being deployed, as these models requires changes in whole Internet infrastructure. Also, prior proposed solutions for provisioning QoS focus on either a single QoS metric or a derived composite metric to find a network path. Focusing on a single metric, however, fails to consider the applications that may require QoS guarantees for multiple metrics. A composite metric may consider multiple metrics by calculating a single value that represents the multiple metrics. However, a composite metric can fail to meet individual QoS constraints.